Fuel pump with lever wear shoe



Jan. 9, 1968 3 w, BRADLEY 3,362,250

FUEL PUMP WITH LEVER WEAR SHOE Filed June 15, 1965 F I G. 4-4.

INVENTOR. WILLIAM A. BRADLEY ATTORNEY United States Patent Cfiiice3,362,250 Patented Jan. 9, 1968 ration of New Jersey Filed June 15,1965, Ser. No. 464,048 Claims. ((Il. 74-569) This invention relates tocontact shoes for eccentric and follower mechanisms and in particular toa contact shoe having a fiat contact face, and means for maintaining theface in constant uniform registry with the eccentric or cam surface.

Fuel pumps and vacuum booster pumps of the draphragm type used onautomotive vehicles, are commonly actuated by a follower leverresiliently urged into contact at one end with a rotating eccentric onthe engine camshaft. In the conventional mechanism, a fiat surface ofthe follower lever preferably makes line contact with the face of theeccentric at the point of tangency. As a result of the limited contact,and the constant service to which mechanisms of this type are put, wearon the lever is severe, so that the service life of the lever isrelatively short.

Heretofore, the problem of excessive or even ordinary wear on the pumplever has been encountered, and in many instances overcome by theprovision of a suitable wear surface so positioned on the lever toachieve a particular function. For example, U.S.P. 2,829,541 illustratesa wear device engageable with a pump lever in such manner to permitmulti-directional movement of the wear device along the lever surface.U.S.P. 2,733,618 illustrates a similar pump lever arrangement having awear device, or shoe, adapted to accommodate a rotating eccentric.

U.S.P. 2,027,332 illustrates a further embodiment of a wear shoe or thelike carried on a pump lever in such manner as to permit relativemovement between the eccentric and the device by means of a pivotalconnection between the shoe and the lever.

It has been found found nonetheless, that with respect to theabove-noted pump lever wear devices, and similar devices designed toovercome excessive wearing away of particular parts, that the problem isnot entirely overcome.

This problem is of course initiated and further aggravated to a largeextent through unavoidable mechanical structure and manufacturingtolerances.

For example, the pump lever or follower arm is normally fabricated as amatter of practical economics as a stamped sheet metal member havingsufiicient structural rigidity to actuate the pump diaphragm. The leveris then pivotally carried in the pump casing. Often, however, the pumpcasing is mounted to an engine block in such manner that the lever issufficiently offset or misaligned as to prohibit making the desired linecontact with the eccentric surface. Further, it has been found that inmany instances,

' the eccentric or cam itself is sufiiciently out of alignment with theco-operating lever such that there is merely a point contact establishedbetween engaging members. Thus, as the eccentric rotates, :an area ofconcentrated wear will be established on the lever arm, the cam surfacemay similarly become worn primarily along one edge.

It is therefore an object of the invention to provide a pump structureadapted particularly to overcome or avoid excessive wear to the pumpactuating lever.

1 Another object of the invention is to provide a substantially flat,inexpensive wear surface for eccentric and follower mechanisms withmeans for maintaining line contact between the face of the wear surfaceand the eccentric surface to minimize wear, and the need for replacementof either of said surfaces.

A further object is to maintain a suitable line contact to establishuniform wear characteristics betwen the eccentric and the wear surfaceregardless of mechanical misalignment of the fuel pump or the pumpmechanism with the eccentric. A still further object is to provide apump lever having a lever arm including a readily replaceable wear padwhich is loosely carried on the arm to provide automatic adjustment tothe cont-acting relationship between the pad and the eccentric surfaces.

These and other objects of the invention not specifically delineated areachieved by providing a portion of the pump lever most normallysusceptible to wear, with a selfaligning replaceable member to absorbsuch wear as a primary function, and to adjust on the surface of thelever in a manner to overcome misalignment present in either the pumpmechanism or in the cam surface.

In the drawings,

FIGURE 1 is an elevation in partial cross section illustrating anautomotive fuel pump attached to a crankcase wall and co-operativelyengaging an engine rotatable eccentric.

FIGURE 2 is a segmentary view on an enlarged scale illustrating the endportion of the pump lever positioned adjacent the eccentric.

FIGURE 3 is a side view in cross section of the device shown in FIGURE2.

FIGURE 4 is an enlarged end view taken along line 4-4 in FIGURE 1.

FIGURE 5 is a sectional view taken along line 5-5 in FIGURE 1.

Structurally, the lever wear pad includes a, relatively hard metallicplate loosely carried on the lever arm in a position to contact theeccentric. The wear plate or pad is fixed relative the lever to avoidlongitudinal movement of the plate on the lever surface, and yet permita limited rotational or rolling movement of the plate along a convexsurface of the lever thereby assuring a proper contact relationship toovercome undesired misalignment of the respective members.

The embodiment of fuel pump shown in FIGURE 1 is of the type found onmany automotive engines and includes basically a body or casing 10 inwhich is positioned inlet and outlet ports, together with inlet andoutlet check valves disposed in a passage connecting the respectiveinlet and outlet ports.

Liquid fuel is introduced to the inlet port 11, communicated with apumping chamber by way of the inlet check valve. The fuel is thereafterurged through the outlet check valve, the outlet port, neither or whichis shown and to the engine carburetor or other point of use.

The pumping chamber is provided along at least one wallwith a flexiblemember such as a diaphragm so positioned to vary the pressure in thepumping chamber and thereby achieve the flow of liqiud fueltherethrough.

The diaphragm is fixed along an air tight seal at its periphery to thepump casing, and is connected through a push rod and spring biasingmeans to an actuating lever 12 which is pivotally hinged by a pin 13 tothe casing w all. Casing 10 includes an opening 14 adapted to registerwith a corresponding opening in the engine crankcase Wall, through whichopening at least a part of actuating lever 12 intrudes.

A biasing spring 16 is compressibly retained on actuating lever 12 andmaintained in place at one end by a downwardly turned tab 17. The otherend of spring 16 is urged into a depression 15 in a wall of the casing10 adjacent opening 14, the effect being to normally bias the protrudingend of lever 12 upwardly.

The driving engine is provided with a cam shaft including a shaft 18 soconnected to the engine drive shaft to be driven at a speed proportionalto the latter. An ec- I? a centric '19 mounted to cam shaft 18 rotatesresponsive to the engine speed.

Referring to FIGURES l and 4, the cam or eccentric 19 is provided with arelatively hard peripheral surface which normally bears against theremote end of lever 12 whereby during -a single rotation of cam 19,lever 12 will be reciprocated through a full cycle in an arcuate pathpivoted about the supporting pin 13. 7

Referring to FIGURES 4 and 5, in one form lever 12 is a stamped steelmember formed preferably in a channel like construction to provide theneeded structural rigidity for withstanding continuous operation andstrain for long periods.

Lever 12 includes an upper connecting wall 21 terminated at itsrespective edges by oppositely disposed and downwardly projecting walls22 and 23. The upper or connecting wall 21 is exteriorly shaped in suchmanner as to provide the upper surface with a convex or arcuateconfiguration.

The primary function of this convex surface configuration is toaccommodate the mating fiat surface of wear pad or plate 24 andsupportably engage the latter in a line contact extending transverselyof the longitudinal axis of the lever 12. Thus, when normally engaged,the outer peripheral surface of eccentric 19 will bear against plate 24and form substantially line contact with the latter thereby tracing awear surface longitudinal to the lever long axis.

The plate 24 may assume any of several positions relative the upper wall21 of the lever and the mating surface of cam 19. In most instances,however, regardless of misalignment of either lever 12 or of thecorresponding cam surface, plate 24 will assume a particular dispositionas dictated by the positions of cam 19 and lever 12, a line contact willalways be maintained at the upper convex surface of lever 12 and thelower fiat surface of the wear plate 24.

For holding wear plate 24 non-fixedly in place on lever 12 convexsurface, the latter is provided with a suitable locking means. Suchlocking means as shown in FIG- URES 2, 3, and 4 includes at least twoupstanding tabs 26 and 27, longitudinally spaced apart and formed toengage the upper surface of wear plate 24. The locking tabs may beformed from the lever by punching, deforming or similar manufacturingoperation. Similarly, they could be welded or fastened to the upperconvex surface of lever 12 to achieve the locking function.

Wear plate 24 is generally thin elongated in shape, and so positioned toslidingly engage the eccentric surface as the latter rotates, therebydefining a substantially rectangular wear pattern on the upper surfaceof the wear plate. Plate 24 is preferably formed of a relatively hardmaterial such as 1050 grade SAE steel or the like, but being preferablyless wear resistant than the cam 19 surface. I

As shown in FIGURES 2, 3, and 4 one embodiment of the locking tabs 26and 27 formed on the lever 12, includes an upstanding central bodyportion 31 which is positioned to register within the projecting ears 32and 33. The respective notches at the ends of plate 24 are of sufficientdepth to be contiguous with walls of the tabs 26 and 27 and permit onlylimited horizontal movement of wear plate 24 along the lever 12 surface.

Laterally extended portions 28 and 29 of the tab 26, bear downwardlyloosely against lever 12 that the latter may be maintained in ahorizontal position, or coplanar with the upper wall of the lever priorto assembly of the latter. The rear tab 27 however, is punched from thelever surface to a generally upright position. Thus, wear plate 24 isproperly positioned by placing the latter on the convex lever surfacesuch that the notch is in registry about the tab27.

Outboard tab 26 is thereafter urged into a substantially uprightposition to bring the outwardly protruding 'ea'r's 28 and 29 intooverlying engagement with the upper surface of the wear plate 24.

With both tabs in place, wear plate 24 is confined to movement in adirection other than longitudinal along the lever surface.

More specifically, and referring to FIGURE 4, the wear plate and thelever 12 during normal operations of the engine, will maintain asubstantially constant relationship. However, as eccentric 19 rotates toadjust its line contact with the wear plate, the latter will bedisplaced into a position on the lever, whereby line contact will beestablished on the lever convex surface. Thus, between the upper surfaceof the wear plate 24 and the eccentric, any misalignment present betweenthe eccentric peripheral surface and the wear plate upper surface willbe neutralized.

In accordance with the present invention, with wear plate 24- heldnon-rigidly on the lever 12 surface, as the eccentric 19 rotates, theline contact maintained with the latter will cause a substantiallyuniform wear of either the cam and more preferably the wear plate in apattern substantially as shown in FIGURE 2 defined by the shaded areabetween lines L-l and L-2.

It is understood that the fastening means for loosely carrying wearplate 24 on the lever may assume any of several embodiments.

For example, rivets or screws suitably attached to the lever 12 may beutilized to connect the wear plate and lever in an operablerelationship.

It can be seen that because of the disclosed simple connectingarrangement wear plate 24 might readily be removed from the lever andreplaced by a new plate with only slight inconvenience, and the simplestof tools.

It will be appreciated by those skilled in the art that the presentembodiment of the novel device represents a preferred form thereof andthat similar arrangements can be applied to the fuel pump withoutdeparting from the spirit and scope of the invention.

What is claimed is:

1. In a mechanical pump for pumping a liquid, said pump including ahousing having a diaphragm forming a pumping chamber with inlet andoutlet valves, means for actuating said diaphragm to effect a pumpingaction on said liquid in said pumping chamber, said actuating meansincluding a lever operably connected to said housing and to saiddiaphragm respectively and having a remote end thereof extending fromthe housing to engage a rotatable drive member for displacing said leverarm to oscillate the diaphragm, the improvement therein of;

(1) a wear plate operably and loosely supported on said lever remoteend, and being urged toward said rotatable drive member,

(2) said lever being provided at said remote end with an arcuate surfacefacing in the direction of said rotatable drive member,

(3) said wear plate having a substantially flat surface disposed incontact with said arcuate surface to permit a limited degree of rollingmovement of said plate on said arcuate surface thereby permitting linecontact between said plate and said arcuate surface regardless ofmisalignment of said lever arm with said drive member, and fasteningmeans disposed at opposed ends of said plate to loosely guide the latterduring said rolling movement of said plate across said arcuate surfaceand to limit the longitudinal I movement of said plate along saidarcuate surface.

2. In a mechanical pump for pumping a liquid, said pump including ahousing having a diaphragm forming a pumping chamber with inlet andoutlet valves, means for actuating said diaphragm to effect a pumpingaction on said liquid in said pumping chamber, said actuating meansincluding a lever arm operably connected to said housing and to saiddiaphragm respectively and having a remote end thereof extending fromthe housing to engage a rotatable drive member for displacing said leverarm to oscillate the diaphragm, the improvement therein of;

( l) a wear plate operably and loosely supported on said lever remoteend, and being urged toward said rotatable drive member,

(2) said lever being provided at said remote end with an arcuate surfacefacing in thedirection of said rotatable drive member,

(3) said wear plate having a substantially fiat surface disposed incontact with said arcuate surface to permit a limited degree of rollingmovement of said plate on said arcuate surface thereby permitting linecontact between said plate and said arcuate surface regardless ofmisalignment of said lever arm with said drive member, and includingfastening means carried on said lever and overlying at least a portionof said elongated plate to loosely position the latter on said convexsurface.

3. In a mechanical pump for pumping a liquid, said pump including ahousing having a diaphragm forming a pumping chamber with inlet andoutlet valves, means for actuating said diaphragm to effect a pumpingaction on said liquid in said pumping chamber, said actuating meansincluding a lever arm operably connected to said housing and to saiddiaphragm respectively and having a remote end thereof extending fromthe housing to engage a rotatable drive member for displacing said leverarm to oscillate the diaphragm,the improvement therein of;

(1) a wear plate operably and loosely supported on said lever remoteend, and being urged toward said rotatable drive member,

(2) said lever being provided at said remote end with an arcuate surfacefacing in the direction of said rotatable drive member,

(3) said wear plate having a substantially flat suarface disposed incontact with said arcuate surface to permit a limited degree of rollingmovement of said plate on said arcuate surface thereby permitting linecontact between said plate and said arcuate surface regardless ofmisalignment of said lever arm with said drive member, wherein saidplate includes;

=(a) a notch formed in opposed ends thereof,

(b) a projection depending outwardly from each side of said notch,

(c) said lever including spaced apart tabs depending from the surfacethereof at opposed ends of said plate, and being loosely positionedbetween and overlying said respective notch projections, therebylimiting horizontal movement of said plate on said convex surface.

4. The combination in a follower arm for a rotatable cam having aperipheral contact surface which includes;

(1) said arm having a remote end disposed adjacent to said camperipheral surface, said remote arm end being provided with an arcuateconfiguration on the surface thereof facing said cam and in a planenormal to the longitudinal axis of said arm,

(2) a wear plate having opposed flat sides, and loosely engaging saidarm end, said plate being interposed between said arm and said cam,

(3) one of said fiat opposed sides bearing against said arcuate surfaceto establish line contact therewith, and,

(4) locking means carried on said remote ends to loosely position saidwear plate to permit a relative rolling movement between said wear plateand said arcuate surface and to avoid relative longitudinal movementtherebetween,

(5) said locking means including a pair of upstanding tabs spacedlongitudinally apart on said arcuate surface, each of said tabsincluding a portion spaced from and overlying said Wear plate to permitsaid rolling movement of said plate along said arcuate surface.

5. The combination in a follower arm for a rotatable cam having aperipheral contact surface which includes;

(1) said arm having a remote end disposed adjacent to said camperipheral surface, said remote arm end being provided with an arcuateconfiguration on the surface thereof facing said cam and in a planenormal to the longitudinal axis of said arm,

(2) a wear plate having opposed fiat sides, and loosely engaging saidarm end, said plate being interposed between said arm and said cam,

(3) one of said opposed sides bearing against said arcuate surface toestablish line contact therewith,

(4) locking means on said remote arm end to loosely position said wearplate and to permit relative rolling movement between said wear plateand said arcuate surface and to avoid relative longitudinal movementtherebetween,

(5 said wear plate including a notch formed at opposed ends thereof, anupstanding tab on said arcuate surface being disposed in each of saidrespective notches to limit longitudinal movement of said wear platealong said arcuate surface.

References Cited UNITED STATES PATENTS 2,207,332 7/ 194-0 Paxton 745 692,827,541 4/1958 Korte 74-5 69 2,829,540 4/ 1958 Niemeyer 745692,877,662 3/ 1959 Woydt 74-569 3,186,351 6/1965 Bradley 103150 FRED C.MATTERN, JR., Primary Examiner. W. S. RATLIFF, Assistant Examiner.

1. IN A MECHANICAL PUMP FOR PUMPING A LIQUID, SAID PUMP INCLUDING AHOUSING HAVING A DIAPHRAGM FORMING A PUMPING CHAMBER WITH INLET ANDOUTLET VALVES, MEANS FOR ACTUATING SAID DIAPHRAGM TO EFFECT A PUMPINGACTION ON SAID LIQUID IN SAID PUMPING CHAMBER, SAID ACTUATING MEANSINCLUDING A LEVER OPERABLY CONNECTED TO SAID HOUSING AND TO SAIDDIAPHRAGM RESPECTIVELY AND HAVING A REMOTE END THEREOF EXTENDING FROMTHE HOUSING TO ENGAGE A ROTATABLE DRIVE MEMBER FOR DISPLAYING AND LEVERARM TO OSCILLATE THE DIAPHRAGM, THE IMPROVEMENT THEREIN OF; (1) A WEARPLATE OPERABLY AND LOSSELY SUPPORTED ON SAID LEVER REMOTE END, AND BEINGURGED TOWARD SAID ROTATABLE DRIVE MEMBER, (2) SAID LEVER BEING PROVIDEDAT SAID REMOTE END WITH AN ARCUATE SURFACE FACING IN THE DIRECTION OFSAID ROTATABLE DRIVE MEMBER, (3) SAID WEAR PLATE HAVING A SUBSTANTIALLYFLAT SURFACE DISPOSED IN CONTACT WITH SAID ARCUATE SURFACE TO PERMIT ALIMITED DEGREE OF ROLLING MOVEMENT OF SAID PLATE ON SAID ARCUATE SURFACETHEREBY PERMITTING LINE CONTACT BETWEEN SAID PLATE AND SAID LEVER ARMWITH REGARDLESS OF MISALIGNMENT OF SAID LEVER ARM WITH SAID DRIVEMEMBER, AND FASTENING MEANS DISPOSED AT OPPOSED ENDS OF SAID PLATE TOLOOSELY GUIDE THE LATTER DURING SAID ROLLING MOVEMENT OF SAID PLATEACROSS SAID ARCUATE SURFACE AND TO LIMIT THE LONGITUDINAL MOVEMENT OFSAID PLATE ALONG SAID ARCUATE SURFACE.